As of today, more than 1000 exoplanets have been discovered.
The variety of the systems unveiled raises the question of
their formation. Because giant planets form faster than
terrestrial planets and shape planetary systems, the study
of their formation and evolution is of prime interest. The
Solar System is our only local laboratory. It is therefore
crucial to study in depth how the Solar System formed and
works to better understand extrasolar systems
Measuring the internal composition of giant planet is the
key to constrain their formation scenario, but our
instruments only allow us to characterize the outermost
layers of these planets, i.e. their atmospheres. Their study
can nonetheless provide key insights on their internal
composition. But because their composition is not only the
result of their formation but also of photochemistry,
dynamics, seasons, and interactions with their environment
(rings/satellites, comets, dust), determining and modeling
their composition in 3D and as a function of time is
essential to constrain their formation and evolution.
Millimeter and submillimeter spectroscopy enables probing
the composition of giant planets atmospheres. Over the last
few years, technical progress in instrumentation has enabled
obtaining new information relative to giant planets
formation and evolution. In this talk, I will present recent
results obtained with (sub-)millimeter telescopes, with an
emphasis on results of the Herschel key program "Water and
related chemistry in the Solar System". I will also
introduce some challenges observers will have to face with
ALMA (Atacama Large Millimeter/submillimeter Array) and the
JUICE (Jupiter Icy Moon Explorer) Submillimetre Wave
Instrument to improve our knowledge of giant planets.